Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Matrix Metalloproteinases”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMedDate not supplied

Messenger RNA for membrane-type 2 matrix metalloproteinase, MT2-MMP, is expressed in human placenta of first trimester.

An intimately regulated cell surface activation of matrix metalloproteinases (MMPs) is believed to be of critical importance for the control of trophoblast invasion. A histological investigation of the expression and localization of three different MMPs, the membrane-type matrix metalloproteinases 1 and 2 (MT1-MMP, MT2-MMP) and matrix metalloproteinase 2 (MMP-2/gelatinase A) was performed by in situ hybridization on consecutive sections from human placentae of first trimester pregnancies. Cytokeratin immunostaining identified trophoblast cells. Both normal and tubal implantation sites were studied. We observed a high degree of coexpression of MT2-MMP, MT1-MMP and MMP-2 mRNAs in single extravillous cytotrophoblasts that had invaded the endometrium and tubal wall. Furthermore, mRNAs for all three genes were also seen in cytotrophoblasts of cell islands. In contrast to this coexpression pattern, MT2-MMP expression was absent from cell columns and decidual cells, in which signals for MT1-MMP and MMP-2 mRNAs were seen. The present data on the cellular expression of MT2-MMP mRNA in placenta extend our knowledge of the proteolytic events that take place during early pregnancy. The data suggest that MT2-MMP, capable of activating MMP-2 in vitro, is involved in the invasion of extravillous cytotrophoblast, possibly related to the physiological activation of MMP-2.

Enzyme Activation↗
PubMed1998

Immunohistochemistry of matrix metalloproteinases (MMP), their substrates, and their inhibitors (TIMP) during trophoblast invasion in the human placenta.

The invasion of extravillous trophoblast cells into the maternal endometrium is one of the key events in human placentation. The ability of these cells to infiltrate the uterine wall and to anchor the placenta to it as well as their ability to infiltrate and to adjust utero-placental vessels to pregnancy depends, among other things, on their ability to secrete enzymes that degrade the extracellular matrix. Most of the latter enzymes belong to the family of matrix metalloproteinases. Their activity is regulated by the tissue inhibitors of matrix metalloproteinases. We have studied the distribution patterns of matrix metalloproteinases-1, -2, -3, and -9 and their inhibitors TIMP-1 and TIMP-2 as compared to the distribution of their substrates along the invasive pathway of extravillous trophoblast of 1st, 2nd, and 3rd trimester placentas by means of light microscopy on paraffin and cryostat sections as well as at the ultrastructural level (only 3rd trimester placenta). The comparison of different methods proved to be necessary, since the immunohistochemical distribution patterns of these soluble enzymes are considerably influenced by the pretreatment of tissues. All three methods revealed immunoreactivities of both, proteinases and their inhibitors, not only intracellularly in the extravillous trophoblast but also extracellularly in its surrounding matrix, the distribution patterns depending on the stage of pregnancy and on the degree of differentiation of trophoblast cells along their invasive pathway. Within the extracellular matrix, immunolocalization of matrix metalloproteinases as well as their inhibitors showed a specific relation to certain extracellular matrix molecules.

Collagen↗
PubMed2002

Gene expression of adhesion molecules and matrix metalloproteinases in endometriosis.

Various types of cell adhesion molecules and matrix metalloproteinases (MMPs) seem to play an important role in the invasion process of endometriosis; however, limited investigation has focused on their gene expression in human peritoneal endometriotic lesions. A total of 63 endometriotic tissues were surgically obtained from 35 women with endometriosis, which included 43 pigmented and 20 non-pigmented lesions. Gene expression levels of E-cadherin, alpha- and beta-catenin, MMP-2, MMP-9 and membrane-type 1 (MT1)-MMP in these endometriotic lesions were compared with those in normal eutopic endometrium obtained from 12 women without endometriosis. MMP-2, MMP-9 and MT1-MMP mRNA expression in pigmented lesions was significantly higher than that in normal endometrium (p < 0.05), whereas E-cadherin, alpha- and beta-catenin mRNA expression was not suppressed in endometriotic lesions. There was a close correlation between MMP-2 or MT1-MMP and E-cadherin, alpha- or beta-catenin gene expression in 63 endometriotic tissues examined (p < 0.01). Immunohistochemical expression of E-cadherin, alpha- and beta-catenin in glandular epithelial cells was positive not only for all of seven cases with normal eutopic endometrium but also for 9 of 11 with ovarian endometriosis. MMP expression in ectopic endometrium was much greater than that in eutopic endometrium. These results suggest that endometriotic tissues expressing MMPs might be invasive and simultaneously possess cell-to-cell adhesion property in pelvic peritoneal foci.

Cadherins↗
PubMed1999

Matrix metalloproteinase-2 activation in human hepatic fibrosis regulation by cell-matrix interactions.

Matrix metalloproteinase-2 (MMP-2) is involved in extracellular matrix remodeling. It is secreted as a proenzyme and activated by membrane type-MMPs (MT-MMP), such as MT1-MMP. In liver fibrosis, MMP-2 is highly expressed in myofibroblasts and may have a profibrogenic role. The mechanisms of its activation in the liver are still unclear. The aim of this work was to show that pro-MMP-2 is efficiently activated in human fibrotic liver and to investigate the role of cell-matrix interactions in this process. Liver specimens obtained from patients with active cirrhosis were compared to normal liver specimens. Human hepatic myofibroblasts were cultured either on plastic, fibronectin, laminin, or on collagen I gels. MMP-2 activity was visualized by gelatin zymography. MMP-2 active form (59 kd) was detected in active cirrhosis but not in normal liver. Myofibroblasts cultured on plastic, fibronectin, or laminin predominantly expressed inactive pro-MMP-2 (66 kd). In contrast, myofibroblasts cultured on collagen I markedly activated the enzyme. Similar results were obtained using membrane fractions from cells previously cultured on collagen or plastic. Activation was inhibited by the tissue inhibitor of metalloproteinases-2 but not by tissue inhibitor of metalloproteinases-1, implicating a MT-MMP-mediated process. Culture on collagen I up-regulated MT1-MMP protein detected by Western blotting, but decreased MT1-MMP mRNA. This study shows that MMP-2 is activated in fibrotic liver. It suggests that interactions between collagen I and myofibroblasts promote this process through a post-translational increase of MT1-MMP expression in these cells.

Cell Adhesion↗
PubMed2002

Anti-tumour necrosis factor (TNF)-alpha therapy (etanercept) down-regulates serum matrix metalloproteinase (MMP)-3 and MMP-1 in rheumatoid arthritis.

OBJECTIVES: Matrix metalloproteinases (MMPs) are cytokine-modulated enzymes that play an important role in the pathogenesis of rheumatoid arthritis (RA) by inducing bone resorption and cartilage destruction. This study evaluated the modulation of serum and synovial MMPs and their inhibitor, tissue inhibitor of matrix metalloproteinases (TIMP)-1, by therapy with soluble tumour necrosis factor (TNF) alpha receptor (etanercept). METHODS: Serum samples were collected from 60 RA patients at baseline and after 8 or 12 weeks of treatment. Paired synovial biopsies were obtained from 11 patients at two time points, before and after 8 weeks of treatment. We measured serum levels of MMP-1, MMP-3 and TIMP-1 by ELISA. Immunohistological analysis of synovial tissue was performed using monoclonal antibodies specific for MMP-1, MMP-3 and TIMP-1. RESULTS: Etanercept therapy significantly down-regulated serum levels of MMP-3 and MMP-1 in parallel with the reduction in inflammatory parameters (C-reactive protein concentration and erythrocyte sedimentation rate) in RA patients. Baseline pretreatment serum levels of MMP-3 correlated with changes in clinical disease activity during therapy. No consistent changes in serum level of TIMP-1 were observed, while ratios of MMP-1 and MMP-3 to TIMP-1 were down-regulated following etanercept treatment. Immunohistochemical analyses revealed great interindividual variability, with generally a high level of expression of MMP and low expression of TIMP. No significant change in the pattern or number of positive cells occurred during therapy. CONCLUSIONS: In RA patients, etanercept therapy down-regulates serum levels of MMP-3 and MMP-1 and the ratio between MMPs and TIMP-1. This may be an important mechanism for the prevention of future development of joint damage.

Adult↗
PubMed2005

Matrix metalloproteinases and their inhibitors in malignant and autoreactive pericardial effusion.

Matrix metalloproteinases (MMPs) are proteolytic enzymes essentially involved in tissue remodeling and tumor invasion, and their activity is counterbalanced by endogenous antagonists, the tissue inhibitors of matrix proteinases (TIMPs). Recent reports have suggested a potential role of MMPs in the evolution of pericardial effusion (PE). In this study, we determined the levels of MMP-2 and MMP-9 and their inhibitors TIMP-1 and TIMP-2 in 19 patients who had malignant PE that was confirmed by histology or cytology and 30 patients who had nonmalignant, autoreactive PE compared with pericardial fluid of 19 patients who had preserved left ventricular function and who underwent aortocoronary bypass surgery for control. Samples were assayed by zymography, immunoblotting, and quantitative enzyme-linked immunosorbent assay. We found significantly higher MMP-2 levels in malignant PE than in pericardial fluid (2,906 +/- 348 vs 1,493 +/- 114 ng/ml, p = 0.0005) or autoreactive PE (2,079 +/- 269 ng/ml, p = 0.01). No significant differences in MMP-9 levels were found between malignant PE and autoreactive PE (83 +/- 28.6 vs 106 +/- 30.4 ng/ml, p = 0.22), whereas MMP-9 was below the detection limit in pericardial fluid. No differences in TIMP-1 levels were found across the different study groups, whereas compared with pericardial fluid, TIMP-2 levels were significantly lower in autoreactive PE (113 +/- 18.9 vs 187 +/- 12.2 ng/ml, p = 0.002). In addition, there was a trend to lower TIMP-2 levels in malignant PE (137 +/- 27.1 ng/ml, p = 0.07). The present findings indicate that proteolytic enzymes and their inhibitors are involved in the pathogenesis of PE, with an expression pattern that depends on etiology. The involvement of MMP-2 in the pathogenesis of malignant PE may indicate a potential role of MMP inhibitors in the control of malignant PE.

Biopsy↗
PubMed2004

A theoretical model of type I collagen proteolysis by matrix metalloproteinase (MMP) 2 and membrane type 1 MMP in the presence of tissue inhibitor of metalloproteinase 2.

One well documented family of enzymes responsible for the proteolytic processes that occur in the extracellular matrix is the soluble and membrane-associated matrix metalloproteinases. Here we present the first theoretical model of the biochemical network describing the proteolysis of collagen I by matrix metalloproteinases 2 (MMP2) and membrane type 1 matrix metalloproteinases (MT1-MMP) in the presence of the tissue inhibitor of metalloproteinases 2 (TIMP2) in a bulk, cell-free, well stirred environment. The model can serve as a tool for describing quantitatively the activation of the MMP2 proenzyme (pro-MMP2), the ectodomain shedding of MT1-MMP, and the collagenolysis arising from both of the enzymes. We show that pro-MMP2 activation, a process that involves a trimer formation of the proenzyme with TIMP2 and MT1-MMP, is suppressed at high inhibitor levels and paradoxically attains maximum only at intermediate TIMP2 concentrations. We also calculate the conditions for which pro-MMP2 activation is maximal. Furthermore we demonstrate that the ectodomain shedding of MT1-MMP can serve as a mechanism controlling the MT1-MMP availability and therefore the pro-MMP2 activation. Finally the proteolytic synergism of MMP2 and MT1-MMP is introduced and described quantitatively. The model provides us a tool to determine the conditions under which the synergism is optimized. Our approach is the first step toward a more complete description of the proteolytic processes that occur in the extracellular matrix and include a wider spectrum of enzymes and substrates as well as naturally occurring or artificial inhibitors.

Animals↗
PubMed2000

Structural studies of matrix metalloproteinases.

The zinc- and calcium-dependent family of proteins called the matrix metalloproteinases are collectively responsible for the degradation of the extracellular matrix. Members of this family such as the collagenases, stromelysins and the gelatinases are involved in the routine tissue remodelling processes such as wound healing, embryonic growth and angiogenesis. Under normal circumstances the proteolytic activity of these proteins are precisely controlled at the transcriptional level, the production of the proteins in their inactive zymogen forms and also by the co-secretion of endogenous inhibitors. Imbalance between the active enzymes and their natural inhibitors leads to the accelerated destruction of connective tissue associated with the pathology of diseases such as rheumatoid and osteoarthritis. The potential for using specific enzyme inhibitors as therapeutic agents to redress this balance has led to intensive research focused on the design, syntheses and molecular structural analyses of low molecular weight inhibitors of this family of proteins. This review describes the essential structural principles and molecular interactions implicated in the innovation of matrix metalloproteinase inhibitors and discusses the features necessary for the specific inhibition of the collagenases.

Catalytic Domain↗
PubMed1998

Matrix metalloproteinases-2 and -9, and tissue inhibitor of metalloproteinases-1 of the sheep placenta during the last third of gestation.

Uteroplacental and fetoplacental blood flows increase dramatically during the last third of gestation. Therefore, angiogenesis and tissue remodelling may regulate placental growth. On days 110, 120, 130, and 142 (term= 145+/-3; n=5 ewes/day) of gestation, sheep placentae were separated into maternal (caruncular and intercaruncular) and fetal (cotyledonary and intercotyledonary) components; tissues were minced and cultured (24 h) and media were analysed for gelatinase activity and for tissue inhibitor of metalloproteinases-1 (TIMP-1) protein. Both the 72-kDa (matrix metalloproteinase-2; MMP-2) and 95-kDa (matrix metalloproteinase-9; MMP-9) gelatinases were detected by zymography. There was more (P<0.001) MMP-2 activity in the caruncle versus intercaruncle and intercotyledon, and all had greater MMP-2 activity (P<0.001) than the cotyledon. There was less (P<0.04) MMP-9 in the intercotyledon than in the other components. By Western analysis, there was more (P<0.004) TIMP-1 (30 kDa) in the caruncle-conditioned media compared to the other tissues, which did not differ from each other (P> or =0.38). The immunohistochemical staining for MMP-2, MMP-9, and TIMP-1 determined that staining was associated with the epithelial cells of the intercotyledon, the uterine glands, cells of the fetomaternal interface of the placentome (trophoblast and binucleate cells), and the endothelial cells of microvessels. Therefore, MMP-2, MMP-9, and TIMP-1 are present in the last third of gestation, suggesting that there is an ongoing tight regulation of tissue remodelling and growth throughout this critical time of pregnancy.

Animals↗
PubMed2005

Endothelial cell regulation of matrix metalloproteinases.

The process of sprouting angiogenesis requires that the endothelial cells degrade the basement membrane matrix and migrate into the interstitial matrix. Matrix metalloproteinases are enzymes capable of cleaving numerous extracellular matrix proteins. Increased production and activity of matrix metalloproteinases in any cell type is associated with a more migratory and invasive phenotype. This paper describes results of recent in-vitro studies of the regulation of transcription and activation of MMP-2 and MT1-MMP in endothelial cells, as well as studies that examined roles of matrix metalloproteinases in activity-induced angiogenesis.

Animals↗
PubMed2002

Release of matrix metalloproteinases following alcohol septal ablation in hypertrophic obstructive cardiomyopathy.

OBJECTIVES: This study examined plasma levels of certain matrix metalloproteinase (MMP) and tissue inhibitor of matrix metalloproteinase (TIMP) species before and after alcohol-induced myocardial infarction (MI) in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Matrix metalloproteinases contribute to tissue remodeling, and endogenous control of MMP activity is achieved by the concordant release and binding of TIMPs. Animal models of MI have demonstrated a role for MMP activation in myocardial remodeling. However, the temporal relationship of MMP and TIMP release following a controlled myocardial injury in humans remains unknown. METHODS: Plasma levels for the gelatinases MMP-2 and MMP-9, and for the collagenases MMP-8 and MMP-13, as well as TIMP-1 profiles were examined (by enzyme-linked immunosorbent assay) at baseline and serially up to 60 h following alcohol injection into the septal perforator artery in order to induce an MI in 51 patients with HOCM (age 55 +/- 2 years). RESULTS: Plasma creatine kinase (MB isoform), indicating myocardial injury, increased 2,150% 18 h post-MI (p < 0.05). Plasma MMP-9 increased by over 400% and MMP-8 by over 100% from baseline values by 12 h post-MI (p < 0.05 vs. baseline). A similar temporal profile was not observed for MMP-2 and MMP-13. In addition, a concomitant increase in plasma TIMP-1 levels did not occur post-MI. As a result, MMP/TIMP stoichiometry (MMP-9/TIMP-1 ratio) increased significantly post-MI, suggestive of reduced TIMP-1 mediated MMP-9 inhibition, which would potentially enhance extracellular myocardial remodeling. CONCLUSIONS: These unique results demonstrated that induction of a controlled myocardial injury in humans, specifically through alcohol-induced MI, caused species- and time-dependent perturbations of MMP/TIMP stoichiometry that would facilitate myocardial remodeling in the early post-MI setting.

Alcohols↗
PubMed2002

The role of the matrix metalloproteinases during in vitro vessel formation.

Matrix metalloproteinases (MMPs) constitute a large family of extracellular matrix degrading proteases implicated in a number of physiological and pathological processes, including angiogenesis. However, the relative importance of the individual MMPs in vessel formation is poorly understood. Using the three-dimensional rat aortic model, the role of the MMPs in angiogenesis in vitro was investigated both by the use of synthetic MMP inhibitors, and by a study of the expression of nine MMPs and three of their endogenous inhibitors (the TIMPs) during vessel formation. Inhibition of microvessel growth in this model by the MMP inhibitor Marimastat demonstrated the requirement of the MMPs for angiogenesis in both collagen and fibrin matrices (half-maximal inhibition at 5 and 80 nM, respectively). The profile of MMP expression was seen to be modified by both matrix composition and exogenous growth factors. For example, whilst the gelatinase MMP-2 and stromelysin MMP-3 were present at high levels in fibrin culture, the stromelysin MMP-11 and membrane-type-1-MMP were more highly expressed during vessel formation in collagen. The angiogenic basic fibroblast growth factor (bFGF) upregulated the expression of the gelatinases (MMP-2 and MMP-9), the stromelysins (MMP-3, MMP-10 and MMP-11) and the interstitial collagenase MMP-13, whereas vascular endothelial growth factor (VEGF) led to a marked increase in expression of MMP-2 only. Together, the environment-dependent upregulation in expression of a number of MMPs during angiogenesis, and the total inhibition of vessel growth observed at nanomolar concentrations of synthetic MMP inhibitors, suggests a major collective role of these enzymes in angiogenesis, and provides a basis for further development of MMP inhibitors for anti-angiogenic therapy.

Animals↗
PubMed2006

Identification and characterization of matrix metalloproteinase-20 (MMP20; enamelysin) genes in reptile and amphibian.

Matrix metalloproteinase-20 (MMP20; enamelysin) is important for proteolytic processing of extracellular matrix (ECM) proteins during the formation of enamel and plays a critical role in proteolytic processing of amelogenin (AMEL), the most abundant enamel ECM protein. MMP20 might have played a role in the emergence of teeth, because jawless vertebrates with primordial teeth on their external skeletons may have possessed the MMP20 gene, and MMP20 and enamel ECM proteins are thought to have evolved together in a special relationship over time. Thus, an understanding of the molecular evolution of the MMP20 gene is important for elucidating the evolution of enamel and it is necessary to identify the orthologs of the MMP20 gene in non-mammals, as it has been identified in mammals. In the present study, orthologs of the MMP20 genes from a reptile (caiman) and an amphibian (African clawed toad) were cloned and characterized. Comparisons of the orthologs revealed that the MMP20 proteins were highly conserved throughout the evolution of tetrapods. Further, the caiman, toad, and mammalian MMP20 shared several unique features specific for MMP20, but not for other matrix metalloproteinases. In addition, the toad MMP20 gene was transcribed only in the upper jaw, presumably in teeth. These results suggest that MMP20 in a common ancestor of tetrapods might have been recruited for the processing of AMEL and conserved over 350 million years of evolution.

Alligators and Crocodiles↗
PubMed2000

A matrix metalloproteinase induction/activation system exists in the human left ventricular myocardium and is upregulated in heart failure.

BACKGROUND: Matrix metalloproteinases (MMPs) contribute to matrix remodeling in disease states such as tumor metastases. Extracellular matrix metalloproteinase inducer (EMMPRIN) has been reported to increase MMP expression, and membrane-type MMP or MT1-MMP has been implicated to activate MMPs. The present study examined whether and to what degree EMMPRIN and MT1-MMP were expressed in human left ventricular (LV) myocardium as well as the association with MMP activity and expression in dilated cardiomyopathy (DCM). METHODS AND RESULTS: LV myocardial zymographic MMP activity increased by >2-fold with both nonischemic DCM (n=21) and ischemic DCM (n=16) compared with normal (n=13). LV myocardial abundance of MMP-9 was increased with both forms of DCM. MMP-2 and MMP-3 were increased with nonischemic DCM. MMP-1 levels were decreased with both forms of DCM. EMMPRIN increased by >250% and MT1-MMP increased by >1000% with both forms of DCM. CONCLUSIONS: Increased LV myocardial MMP activity and selective upregulation of MMPs with nonischemic and ischemic forms of DCM occurred. Moreover, a local MMP induction/activation system was identified in isolated normal human LV myocytes that was upregulated with DCM. The control of MMP activation and expression in the failing human LV myocardium represents a new and potentially significant therapeutic target for this disease process.

Adolescent↗
PubMed2005

The effect of sativan from Viola verecunda A. Gray on the expressions of matrix metalloproteinase-1 caused by ultraviolet irradiated cultured primary human skin fibroblasts.

Matrix metalloproteinases (MMPs) are a family of enzymes whose main function is degradation of the extracellular matrix. Matrix metalloproteinase-1 (MMP-1) degrades type I procollagen constituting the major structural component of the basement membrane and extra cellular membrane. The enzymatic activity is found to be elevated in photoaging. With the aim of finding novel MMP-1 inhibitors from natural products, 15 extracts of the Viola taxa, which are used as prescriptions for skin eruption treatment in traditional medicine, were screened for their inhibitory activities towards MMP-1. Among the 15 tested materials, the methanol extracts of Viola hondoensis W. BECKER et H. BOISS, Viola ibukiana MAKINO, Viola lactiflora NAKAI and Viola verecunda A. GRAY were potential inhibitory to MMP-1, and other Viola taxa showed a weak inhibitory effect at a concentration of 100 microg/ml. We investigated the effect of MMP-1 inhibitory of the solvent fractions of the same plants (Viola hondoensis, Viola ibukiana and Viola verecunda). Therefore, a strong inhibition was found in the ethylacetate fractions of Viola verecunda with inhibitory activity (>90%) at a concentration of 10 microg/ml. Here we investigated the effect of sativan isolated from the ethylacetate fractions of Viola verecunda on the expression of MMPs in UV-irradiated human skin fibroblasts in vitro. Sativan markedly reduced UV-induced MMP-1 expression at the protein levels in a dose-dependent manner. Our report is the first description for the ability of sativan to regulate UV-induced MMP-1 expression.

Cells, Cultured↗
PubMedDate not supplied

The influence of sequential, in vitro passage on secretion of matrix metalloproteinases by human brain tumour cells.

Matrix metalloproteinases (MMP) are a family of zinc-dependent enzymes which degrade various components of the extracellular matrix (ECM) and play an important role in facilitating tumour cell invasion of the normal brain. The family includes the gelatinases, stromelysins and collagenases. Preliminary studies have shown that there is a differential expression four metalloproteinases in human brain tumour cell lines derived from neoplasms of various histological types and grades of malignancy. Morphological and antigenic changes in human glioma-derived cell lines over many serial in vitro passages have been reported in earlier studies. When established cell lines are maintained in culture over a long period, it is possible that the secretion of enzymes such as metalloproteinases may differ according to the passage level examined. This report presents a study on the secretion of four matrix metalloproteinases - interstitial collagenase (MMP-), 72-kDa and 92-kDa gelatinases (MMP-2 and MMP-9 respectively), and stromelysin (MMP-3) - in three human brain tumour-derived cell lines at sequentially increasing passage numbers, ranging from passage 2 to passage 50; foetal astrocytes were used as a positive control. Reverse zymography and substrate degradation analysis were employed to demonstrate the presence of these enzymes in cell- conditioned culture medium. Aminophenyl mercuric acetate (APMA) was used to activate latent zymogen. Results demonstrate that there is no definite pattern of change in the levels of enzyme secretion common to all cell lines studied. Instead, the fluctuations in APMA- activated metalloproteinase activity in serial passage seems to vary considerably depending on the cell line and the type of enzyme studied. The variation in metalloproteinase expression observed on serial passage may be due to in vitro selection processes or karyotype evolution where the transcription of either the enzyme and/or its inhibitor may be affected. Thus an imbalance of the two products could be occurring in serial passage. Ideally, experiments requiring the measurement of relative enzyme activities should use cultures as near to the biopsy stage as possible, i.e. very low passages, to avoid artifacts that may arise on prolonged culturing.

Astrocytoma↗
PubMed1997

Relation of enhanced secretion of active matrix metalloproteinases with tumor spread in human hepatocellular carcinoma.

BACKGROUND & AIMS: Matrix metalloproteinases have been implicated in invasion and metastasis of various human malignant tumors, but its role in human hepatocellular carcinoma has not been characterized in detail. The aim of the present study was to examine the secretion and activation of metalloproteinases in liver tissues from patients with hepatocellular carcinoma and evaluate its relationship with clinicopathologic characteristics. METHODS: Activity of metalloproteinases was measured in 30 surgical specimen pairs of human primary hepatocellular carcinoma and adjacent nontumoral liver and in five cultured human hepatoma cell lines using zymography. A comparison of this activity with clinicopathological features was made. RESULTS: In the liver tissues, enhanced secretion of active forms of gelatinase A and matrilysin was associated with portal venous invasion (P < 0.05, respectively), intrahepatic metastasis (P < 0.05, respectively), and recurrence within the first postoperative year (P < 0.01 and P < 0.05, respectively). Enhanced messenger RNA expression for membrane type 1-matrix metalloproteinase was observed in 22 of 30 cases and associated with capsule invasion and the activation of progelatinase A (P < 0.05, respectively). CONCLUSIONS: Active gelatinase A, active matrilysin, and membrane type 1-matrix metalloproteinase may play an important role in tumor spread of human hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1999

Activation of matrix metalloproteinase-2 in human breast cancer cells overexpressing cyclooxygenase-1 or -2.

Human breast cancer cell line Hs578T was stably transfected with cDNA for cyclooxygenase-1 or -2. When the cells overexpressing cyclooxygenase-1 or -2 were stimulated with concanavalin A, the processing of matrix metalloproteinase-2 was observed with the aid of gelatin zymography. This processing was not seen in mock-transfected and original cells which did not express detectable cyclooxygenase activity. Furthermore, Northern blotting showed 8-13 fold induction of membrane-type 1 matrix metalloproteinase which processed matrix metalloproteinase-2 in the cells expressing cyclooxygenases. These findings suggest that both isoforms of cyclooxygenase mediate the processing of matrix metalloproteinase-2 through induction of membrane-type I metalloproteinase in breast cancer cells.

Breast Neoplasms↗